1. Field of the Invention
The present invention relates to input apparatuses for moving a pointer or a figure displayed on a computer screen, and more particularly, to a data input apparatus providing easy operation even for large movement on the screen.
2. Description of the Related Art
As a data input apparatus for a computer, there have been used various types of apparatuses, such as a mouse type operated on a desk, a trackball type in which a spherical ball is operated, built in a notebook-type personal computer or used as a single unit, a touch-sensitive pad type which the user rubs by a finger, and a joystick type. With these input apparatuses, a character for indicating the current position, such as a cursor and a pointer, displayed on a computer screen is moved to the desired position.
FIG. 5 is a plan of a conventional data input apparatus employing a trackball.
A spherical operation member 1 called a trackball is supported rotatably in the three-dimensional space and drives an X encoder 2 and a Y encoder 3.
The X encoder 2 has a roller 2a rotating about an axis extending in the Y direction and a circular plate 2b rotating together with the roller 2a. At the periphery of the circular plate 2b, notches are formed at a certain interval in the circumferential direction. A optocoupler 2c is disposed at part of the periphery of the circular plate 2b so as to sandwich the plate. In the optocoupler 2c, a light-emitting device and a light-receiving device are disposed oppositely, and the periphery of the circular plate 2b is disposed between the light-emitting device and the light-receiving device. When the roller 2a and the circular plate 2b rotate, a pulse output having the frequency corresponding to the rotation speed of the circular plate 2b is obtained from the optocoupler 2c as an operation signal.
In the same way, the Y encoder 3 has a roller 3a rotating about an axis extending in the X direction, a circular plate 3b rotating together with the roller 3a, and an optocoupler 3c disposed at a part of the periphery of the circular plate 3b so as to sandwich the plate. At the periphery of the circular plate 3b, notches are formed at a certain interval in the circumferential direction. A pulse output having the frequency corresponding to the rotation speed of the roller 3a and the circular plate 3b is obtained from the optocoupler 3c.
A general input operation will be described below in a case when this trackball-type input apparatus is connected to a computer.
When the spherical operation member 1 is rotated in the X direction, the roller 2a and the circular plate 2b of the X encoder 2 rotate. A pulse output is obtained from the optocoupler 2c and is converted to coordinate data. When this coordinate data is input to the computer, a cursor, a pointer or a character displayed on a screen connected to the computer is moved in the X direction. When the spherical operation member 1 is rotated in the Y direction, the roller 3a and the circular plate 3b of the Y encoder 3 rotate. A pulse output obtained from the optocoupler 3c is converted to coordinate data. When this coordinate data is input to the computer, the cursor or the pointer is moved in the Y direction on the screen.
When the operation member 1 is rotated, for example, in the direction indicated by .alpha., which is at angles from the X and Y axes, both rollers 2a and 3a rotate. Pulses obtained from the optocouplers 2c and 3c are converted to coordinate data, and the cursor or the pointer is moved in the direction indicated by .alpha. on the screen.
According to the screen size and the movement speed of the cursor, the operation member 1 is rotated once or a plurality of times to move the cursor to the desired position in the two-dimensional manner.
When the screen size of a display unit connected to the computer is large, it may be required to move the cursor or the pointer long. In this case, by the use of the trackball-type input apparatus, the operation member 1 (trackball) needs to be rolled a number of times by a finger and hence easy operation is not provided.
In a usual touch-sensitive-pad-type input apparatus, the pad is rubbed by the digital pulp of a finger. When the cursor needs to be moved long, like the situation for the trackball-type input apparatus, inputs are repeatedly required by reciprocating the finger on the pad. This operation is troublesome.
A mouse-type input apparatus can move in a limited area due to the use of a mouse pad or a space on a desk. Therefore, to move the cursor or the pointer long, it is necessary to reciprocate the mouse a number of times. Easy operation is not provided.
With the use of a joystick-type input apparatus, the cursor or the pointer can be moved just by leaning the stick section in the desired direction and the movement continues while the stick section is being leaned. Whereas the cursor can be continuously moved with the use of the joystick-type input apparatus without reciprocating a hand or a finger a number of times, the apparatus is unsuitable for precise positioning on the screen.
To reduce reciprocative movement of a hand or a finger, the movement speed of the cursor or the pointer can be increased by a setting of an input apparatus or an internal setting of the computer to extend a movement distance. When the movement speed of the cursor or the pointer is very high, precise positioning is difficult to achieve. Although the diameter of the trackball can be extended or the area of a touch-sensitive pad or the mouse pad can be enlarged, the condition is not improved due to a space required for installation on the computer or the desk.